Field of the Invention
The present invention relates to an image processing technique of detecting and managing an object in image data.
Description of the Related Art
As digital still cameras (to be also referred to as “DSCs” hereinafter) become popular, image data as many as several thousands or several ten thousands need to be handled nowadays. As one especially important technique for the handling method, personal recognition is implemented by handling images based on a person's face. For example, a face region included in an input image is detected in advance, information (to be referred to as a “feature amount” hereinafter) obtained by analyzing the detected face image is extracted, and the extracted feature amount is registered. Note that the feature amount to be registered increases in accordance with the number of images to be analyzed and the number of faces included in an image. A database in which a plurality of feature amounts are registered will be called a “dictionary” or “face dictionary”. Personal recognition becomes possible by collating an obtained face dictionary with a feature amount obtained by analyzing a newly input image.
Japanese Patent No. 3469031 discloses an arrangement for evaluating and determining whether a face newly detected from an image should be registered in a face dictionary.
However, in Japanese Patent No. 3469031, incorrect determination may occur regardless of how to select a face to be registered in the face dictionary. The incorrect determination means a situation in which a person, who has already been recognized, is generated as a new different person as a result of recognition.
An example of the incorrect determination will be described in detail. When many images are scanned, many image feature amounts are registered in a dictionary. At this time, exceptional feature amounts are sometimes registered in the dictionary even for a family as a result of exceptional capturing. In such a case, a plurality of persons are generated even for the same person as identification results.
Also, in Japanese Patent No. 3469031, an object (for example, a passer irrelevant to the user) other than a target object may be registered in the face dictionary. A situation in which an object other than a target one is identified will be called “erroneous determination”.
Repetition of incorrect determination and erroneous determination impairs the personal recognition accuracy based on the face dictionary.